OS-XXX sdev plugin should not force number of the beast

no-666.patch

commit efd2c605947a09c8c641ec66ec327082fa62f239
Author: Mike Gerdts <[email protected]>
Date:   Sat Dec 30 05:18:57 2017 +0000

    OS-XXX sdev plugin should not force number of the beast

diff --git a/usr/src/uts/common/fs/dev/sdev_plugin.c b/usr/src/uts/common/fs/dev/sdev_plugin.c
index dd81a52..58f7256 100644
--- a/usr/src/uts/common/fs/dev/sdev_plugin.c
+++ b/usr/src/uts/common/fs/dev/sdev_plugin.c
@@ -272,24 +272,29 @@ sdev_plugin_mknod(sdev_ctx_t ctx, char *name, mode_t mode, dev_t dev)
        sdev_node_t *sdvp;
        timestruc_t now;
        struct vattr vap;
+       mode_t devmode = mode & (S_IFCHR | S_IFBLK);
 
        if (sdev_plugin_name_isvalid(name, SDEV_PLUGIN_NAMELEN) == 0)
                return (EINVAL);
 
        sdvp = (sdev_node_t *)ctx;
        ASSERT(RW_WRITE_HELD(&sdvp->sdev_contents));
-       if (mode != S_IFCHR && mode != S_IFBLK)
+       if (devmode != S_IFCHR && devmode != S_IFBLK)
                return (EINVAL);
 
+       /* Default to relatively safe permission bits if none specified. */
+       if ((mode & 0666) == 0)
+               mode = devmode | 0600;
+
        ASSERT(sdvp->sdev_private != NULL);
 
-       vap = *sdev_getdefault_attr(mode == S_IFCHR ? VCHR : VBLK);
+       vap = *sdev_getdefault_attr(devmode == S_IFCHR ? VCHR : VBLK);
        gethrestime(&now);
        vap.va_atime = now;
        vap.va_mtime = now;
        vap.va_ctime = now;
        vap.va_rdev = dev;
-       vap.va_mode = mode | 0666;
+       vap.va_mode = mode;
 
        /* Despite the similar name, this is in fact a different function */
        return (sdev_plugin_mknode(sdvp->sdev_private, sdvp, name, &vap));
diff --git a/usr/src/uts/common/io/vnd/vnd.c b/usr/src/uts/common/io/vnd/vnd.c
index 27fdba6..1bd1743 100644
--- a/usr/src/uts/common/io/vnd/vnd.c
+++ b/usr/src/uts/common/io/vnd/vnd.c
@@ -5418,8 +5418,9 @@ vnd_sdev_fillzone(vnd_pnsd_t *nsp, sdev_ctx_t ctx)
                mutex_enter(&vdp->vdd_lock);
                if ((vdp->vdd_flags & VND_D_LINKED) &&
                    !(vdp->vdd_flags & (VND_D_CONDEMNED | VND_D_ZONE_DYING))) {
-                       ret = sdev_plugin_mknod(ctx, vdp->vdd_lname, S_IFCHR,
-                           vdp->vdd_devid);
+                       /* XXX-mg 0666 added for compatibility.  Dubious. */
+                       ret = sdev_plugin_mknod(ctx, vdp->vdd_lname,
+                           S_IFCHR | 0666, vdp->vdd_devid);
                        if (ret != 0 && ret != EEXIST) {
                                mutex_exit(&vdp->vdd_lock);
                                mutex_exit(&nsp->vpnd_lock);
@@ -5463,7 +5464,8 @@ vnd_sdev_filldir_root(sdev_ctx_t ctx)
         * Always add a reference to the control node. There's no need to
         * reference it since it always exists and is always what we clone from.
         */
-       ret = sdev_plugin_mknod(ctx, "ctl", S_IFCHR,
+       /* XXX-mg 0666 added for compatibility.  Dubious. */
+       ret = sdev_plugin_mknod(ctx, "ctl", S_IFCHR | 0666,
            makedevice(ddi_driver_major(vnd_dip), 0));
        if (ret != 0 && ret != EEXIST)
                return (ret);

sdev_ctx_minor.patch

commit 97c495beb6e4dc7330046e5f8198a98b638d7d4e
Author: Mike Gerdts <[email protected]>
Date:   Sat Dec 30 00:11:14 2017 +0000

    OS-XXXX sdev_plugin needs a gitminor function

diff --git a/usr/src/uts/common/fs/dev/sdev_plugin.c b/usr/src/uts/common/fs/dev/sdev_plugin.c
index 8851911..dd81a52 100644
--- a/usr/src/uts/common/fs/dev/sdev_plugin.c
+++ b/usr/src/uts/common/fs/dev/sdev_plugin.c
@@ -145,6 +145,21 @@ sdev_ctx_name(sdev_ctx_t ctx)
        return (sdp->sdev_name);
 }
 
+int
+sdev_ctx_minor(sdev_ctx_t ctx, minor_t *minorp)
+{
+       sdev_node_t *sdp = (sdev_node_t *)ctx;
+
+       ASSERT(RW_LOCK_HELD(&sdp->sdev_contents));
+       if (sdp->sdev_vnode->v_type == VCHR ||
+           sdp->sdev_vnode->v_type == VBLK) {
+               *minorp = sdp->sdev_vnode->v_rdev;
+               return (0);
+       }
+
+       return (ENODEV);
+}
+
 /*
  * Currently we only support psasing through a single flag -- SDEV_IS_GLOBAL.
  */
@@ -159,7 +174,8 @@ sdev_ctx_flags(sdev_ctx_t ctx)
 
 /*
  * Return some amount of private data specific to the vtype. In the case of a
- * character or block device this is the device number.
+ * character or block device this is the device number.  So as to not confuse
+ * NULL and minor 0, a better interface for minor numbers is sdev_ctx_minor().
  */
 const void *
 sdev_ctx_vtype_data(sdev_ctx_t ctx)
diff --git a/usr/src/uts/common/sys/fs/sdev_plugin.h b/usr/src/uts/common/sys/fs/sdev_plugin.h
index 8783df5..bfa4ce7 100644
--- a/usr/src/uts/common/sys/fs/sdev_plugin.h
+++ b/usr/src/uts/common/sys/fs/sdev_plugin.h
@@ -88,6 +88,7 @@ typedef enum sdev_ctx_flags {
 extern sdev_ctx_flags_t sdev_ctx_flags(sdev_ctx_t);
 extern const char *sdev_ctx_name(sdev_ctx_t);
 extern const char *sdev_ctx_path(sdev_ctx_t);
+extern int sdev_ctx_minor(sdev_ctx_t, minor_t *);
 extern enum vtype sdev_ctx_vtype(sdev_ctx_t);
 extern const void *sdev_ctx_vtype_data(sdev_ctx_t);
 

sdev_plugins.9f

SDEV_PLUGINS(9F)         Kernel Functions for Drivers         SDEV_PLUGINS(9F)

NAME
     sdev_plugins - plugin interfaces for dev(7FS)

SYNOPSIS
     #include <sys/fs/sdev_plugin.h>

     sdev_plugin_hdl_t
     sdev_plugin_register(const char *name, sdev_plugin_ops_t *sdev_ops,
         int *errp);

     void
     sdev_plugin_unregister(sdev_plugin_hdl_t sdev_hdl);

     sdev_ctx_flags_t
     sdev_ctx_flags(sdev_ctx_t sdev_ctx);

     const char *
     sdev_ctx_name(sdev_ctx_t sdev_ctx);

     const char *
     sdev_ctx_path(sdev_ctx_t sdev_ctx);

     int
     sdev_ctx_minor(sdev_ctx_t sdev_ctx, minor_t *minorp);

     vtype_t
     sdev_ctx_vtype(sdev_ctx_t sdev_ctx);

     void *
     sdev_ctx_vtype_data(sdev_ctx_t sdev_ctx);

     int
     sdev_plugin_mkdir(sdev_ctx_t sdev_ctx, const char *dirname);

     int
     sdev_plugin_mknod(sdev_ctx_t sdev_ctx, const char *devname, mode_t mode,
         dev_t dev);

INTERFACE LEVEL
     Evolving - This interface is still evolving in illumos.  API and ABI
     stability is not guaranteed.

PARAMETERS
     sdev_hdl      A sdev_plugin_hdl_t handle, as described in the Plugin
                   Registration section.

     sdev_ops      Pointer to sdev_plugin_ops_t structure, as described in the
                   Plugin Registration section.

     sdev_ctx      An opaque context passed to the plugin by dev(7FS) to the
                   various callbacks.  See the Context Helper Functions
                   section for details.

DESCRIPTION
     The sdev_plugins interfaces described in this page are used to
     dynamically generate directories and device nodes within the /dev
     directory.  They obviate the need for devfsadm(1M) plugins for modules
     that use these interfaces.

   Plugin registration
     The sdev_plugin_register() function is used to register initial path and
     the callbacks used by dev(7FS) as /dev is traversed.  The
     sdev_plugin_ops_t type is defined as:

         typedef struct sdev_plugin_ops {
                 int spo_version;
                 sdev_plugin_flags_t spo_flags;
                 sp_valid_f spo_validate;
                 sp_filldir_f spo_filldir;
                 sp_inactive_f spo_inactive;
         } sdev_plugin_ops_t;

     The value of spo_version should be set to SDEV_PLUGIN_VERSION and
     spo_flags may include the following:

           SDEV_PLUGIN_NO_NCACHE
                         XXX FIXME

           SDEV_PLUGIN_SUBDIR
                         This plugin will create devices in a subdirectory of
                         /dev with a name matching that of the name argument.

     See the Callbacks section for details on the spo_validate, spo_filldir,
     and spo_inactive callbacks.

     The structure referenced by the sdev_ops variable may be used by dev(7FS)
     until sdev_plugin_unregister() is called with the same sdev_plugin_hdl_t
     as was returned by the earlier call to the sdev_plugin_register()
     function.

   Callbacks
     dev(7FS) will call the callback functions defined in the
     sdev_plugin_ops_t as the system accesses relevant paths through the /dev
     directory.

     Callbacks make extensive use of Context Helper Functions.  Additionally,
     they will call into dev(7FS) to create subidrectories and device nodes
     with the following functions.

     int sdev_plugin_mkdir(sdev_ctx_t ctx, const char *dirname)

           Creates a subdirectory named dirname within the directory
           referenced by ctx.

     int sdev_plugin_mknod(sdev_ctx_t ctx, const char *nodename, mode_t mode,
     dev_t dev)

           Creates a block or character device named nodename within the
           directory referenced by ctx.  The mode argument must contain
           S_IFCHR or S_IFBLK.  If no other read or write mode bits are set,
           S_IREAD|S_IWRITE (0600) is assumed.  See stat.h(3HEAD).  The dev
           argument is as returned by makedev(3C).

     The following callbacks must be implemented by every plugin.

     sdev_plugin_validate_t spo_validate(sdev_ctxt_t ctx)

           The validate callback is called to verify that a particular device
           node or directory is still valid.  The callback shall return one of
           the following values:

           SDEV_VTOR_INVALID
                         The directory or device node is no longer valid and
                         should be removed.

           SDEV_VTOR_SKIP
                         XXX

           SDEV_VTOR_VALID
                         The directory or device node is valid and should not
                         be changed.

           SDEV_VTOR_STALE
                         The directory or device node should be present, but
                         it is stale and should be regenerated.  XXX This
                         triggers spo_filldir?

     int spo_filldir(sdev_ctxt_t ctx)

           The fill directory callback is called to generate or re-generate
           the contents of a directory.  This callback will typically make one
           more calls to the spo_plugin_mkdir() and/or spo_plugin_mknod()
           functions to create directories and device nodes.  This callback
           should be tolerant of being called on a directory that is already
           partially filled.  That is, spo_plugin_mkdir() and
           spo_plugin_mknod() may return EEXIST which is likely not a fatal
           error.

           The callback shall return 0 on success or a valid errno value on
           falure.

     void spo_inactive(sdev_ctxt_t ctx)

           The inactive callback is called when dev(7FS) is removing an entry.
           This callback should be used by the module to reduce reference
           counts and/or any other house keeping that is required as device
           nodes are removed.

     If the device(s) are different between the global zone and non-global
     zones, callbacks should use sdev_ctx_flags() to check for the SDEV_GLOBAL
     flag.

     If a module creates a directory hierarchy, sdev_ctx_path() will be
     essential to ensuring that operations are being performed in the intended
     directory.

   Context Helper Functions
     Context helper functions are used within callbacks to gain access to
     various fields within sdev_ctxt_t structures.  See the Callbacks section.

     The sdev_ctx_flags() function may retrieve the flags for a particular
     directory or device node.  The supported flags are:

           SDEV_GLOBAL   This dev(7FS) instance is in the global zone.

     The sdev_ctx_name() function returns the last component of the path of
     the directory or device node.

     The sdev_ctx_path() function returns the absolute path of the directory
     or device node.

     The sdev_ctx_minor() function returns via the location referenced by
     minorp the minor node of the device node referenced by the sdev_ctx
     function argument.  If sdev_ctx does not refer to a block or character
     device, an error is returned and the location referend by minorp is not
     changed.

     The sdev_ctx_vtype() function returns the vnode type of the vnode
     corresponding to element referenced by the sdev_ctx function argument.
     The following values are expected:

           VDIR          Directory

           VBLK          Block device

           VCHR          Character device

     The dev_ctx_vtype_data() function is obsolete.  Use dev_ctx_minor()
     instead.

CONTEXT
     These functions may be called only in kernel context.

RETURN VALUES
     The sdev_plugin_register() function returns a non-NULL value on success.
     On failure it returns NULL and if errp is non-NULL, errp is set to an
     appropriate errno value.  If sdev_ops is not properly initialized, this
     value will be EINVAL.  If the plugin is already registered or there is
     another name collision, EEXIST is returned via errp.

SEE ALSO
     devfsadm(1M), makedev(3C), stat.h(3HEAD), dev(7FS)

illumos                        December 30, 2017                       illumos